Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Membrane filtration systems typically can be operated in a single or double-ended manner. That is, filtrate can be withdrawn from one or both ends of the membranes, particularly when the membranes are in the form of tubes or fibres. Double-ended systems are typically more efficient in that more permeate can be withdrawn from the membranes within a set period due to reduced pressure drop along the length of the membrane.
Similarly, the efficiency of the membrane filtration systems is typically dependent on the surface area of the membrane exposed to liquid to be filtered. In the case of filtration systems using bundles of membranes tubes or fibres, the surface area of the system may be increased by a number of methods including increasing the packing density of the tubes or fibres and/or by increasing the length of the tubes or fibres extending between their end supports.
The success of a membrane filtration process largely depends on employing an effective and efficient membrane cleaning method. Porous membrane filtration systems require regular backwashing of the membranes to maintain filtration efficiency and flux while reducing transmembrane pressure (TMP) which rises as the membrane pores become clogged with impurities. Typically, during the backwash cycle the impurities are forced out of the membrane pores and/or scoured from the membrane surfaces into the feed tank or cell by one or more of pressurised gas, gas bubbles, liquid, or a mixture thereof. The liquid containing impurities and deposits from the membranes is then drained or flushed from the tank.
Minimising the footprint of filtration systems is desirable in terms of space eventually occupied by the filtration plant. Compact systems have lower cost, less waste volume, lesser impact on the environment and are more acceptable to the market.